Resilient surface coverings, and in particular resilient floor coverings, are well known in the art. The floor coverings which are in wide use today are primarily of vinyl construction and, although they can be constructed to have varying degrees of flexibility, they are "resilient" when compared to conventional natural materials, such as ceramic tile. A variety of such products are commercially available and these products have proven to exhibit good wear resistance; however, such coverings are not without certain deficiencies. For example, although vinyl flooring products are durable and stain resistant, they nevertheless tend to lose their glossy appearance through wear. A high-gloss appearance for a floor covering is often desired. Accordingly, the manufacturers of such materials have long sought to find improved floor coverings which exhibit good gloss retention.
One method of providing improved gloss retention is through the application of polyurethane or other wear layers to vinyl flooring structures. Such materials are durable and relatively scratch resistant, and they tend to retain their high-gloss appearance over a longer period of time than do vinyl-surfaced flooring structures. Nevertheless, these wear layers, and in particular polyurethane wear layers, also have certain drawbacks. For example, they are more susceptible to staining; thus, when exposed to common household stains as ballpoint pen, lipstick, mustard, shoe polish and the like, polyurethane coatings tend to be more easily stained than vinyl coatings.
Another method has been to provide gloss retention and improved stain resistance by the use of different types of urea- or melamine-formaldehyde resins, often referred to as aminoplasts, as disclosed in Bolgiano et al. U.S. Pat. No. 4,781,987, which is incorporated herein by reference. While such wear layers have improved stain resistance, the improvement has come at the sacrifice of flexibility. To obtain a greater degree of flexibility, urethane is incorporated into the wear layer composition which again degrades the stain resistance.
Accordingly, one objective of the present invention is to provide an aminoplast wear layer for resilient surface coverings having increased flexibility and improved stain resistance.
Another object of the present invention is to permit the use of reduced levels of urethane in aminoplast wear layers for resilient surface coverings.
A further object of the present invention is to provide a method of controlling gloss level of an aminoplast wear layer without substantially affecting the other performance properties of the wear layer including stain resistance, adhesion, gloss retention and scuff resistance.
A still further object of the present invention is to provide a wear layer and method of making the wear layer having areas of different gloss level.
These and other advantages of the present invention will become apparent from the detailed description of the preferred embodiments which follow.